When a protocol is designed based on assumption that stations transmit and receive signals omni-directionally in a Wireless Local Area Network (WLAN) or a Wireless Personal Area Network (WPAN) environment, communication may be performed without a need to modify the protocol even though signals are transferred through relaying for a coverage extension.
However, in a case where communication is performed using a directional antenna, when a transmitting station is aware of a position of a relay station, the transmitting station may transmit data into a direction towards a recipient station. Accordingly, in this case, a procedure of obtaining position information to relay communication between stations may be required.
In particular, millimeter wave (mmWave) such as 60 GHz of which a standardization is ongoing may be used to transmit data at a transmission rate of few Gbps using a wideband of about 2 GHz according to a simple modulation scheme. However, due to characteristics of a high frequency wave, mmWave may have strong straightness and great path loss. Accordingly, to complement the above disadvantages, a high antenna gain may be obtained by gathering a transmit power into a predetermined direction, not omni-directions, using a directional antenna.
In this instance, an array gain may be obtained by discovering a direction of the directional antenna using a facing direction between a transmitting station and a recipient station, or by discovering the direction of the directional antenna using a beamforming process for adjusting an amplitude or a phase of each of antennas constituting an antenna array.